1. Field of the Invention
This invention relates to telephones utilizing variable color display.
2. Description of the Prior Art
A display device that can change color and selectively display digits and characters is described in my U.S. Pat. No. 4,086,514, entitled Variable Color Display Device and issued on Apr. 25, 1978. This display device includes display areas arranged in a suitable display font, such as well known 7-segment display font, which may be selectively energized in groups to display all known characters. Each display segment includes three light emitting diodes for emitting light signals of respectively different primary colors, which are blended within the display segment to form a composite light signal. The color of the composite light signal can be controlled by selectively varying the portions of the primary light signals.
Commercially well known telephone has a capability to establish a telephone call of a selective type by dialing appropriate number. A telephone with monochromatic digital display, disclosed in U.S. Pat. No. 3,932,709 issued on Jan. 13, 1976 to Don G. Hoff et al., has additional capability to display dialed number in a single color to verify its correctness. When placing a long distance call, it is usually necessary to precede the local telephone number by appropriate area code. No provision is made in the prior art telephones for distinguishing between the area code portion and local number portion when displaying such a telephone number.
Telephone with variable color digital display is unknown.